#!/bin/bash

set -Eeu -o pipefail

# Note: net-traffic uses interval type 'repeat' so cannot use button events.
# See https://github.com/vivien/i3blocks#interval

# some default values for arguments"
UP=${label_icon:-$(xrescat i3xrocks.label.up " up")}
DN=${label_icon:-$(xrescat i3xrocks.label.dn " dn")}
DLY=${DLY:-5}
ERROR_DLY=${ERROR_DLY:-10}
RT=${RT:-}

# Padding the output to 5 characters to avoid jittering on the bar
NUMFMT="numfmt --to iec --format %f --padding 5"

# determine the net interface name, but only use one interface
# there could be several default routes, if you have a VPN for example
IF="${BLOCK_INSTANCE:-$(awk '$2 == 00000000 && $1 !~ /(ppp|tun|tap)/ { print $1; exit }' < /proc/net/route)}"

IF_PATH="/sys/class/net/${IF}"

if [ -d "${IF_PATH}/bonding" ]; then
  # this is a bond, use the active slave's interface
  IF="$(< "${IF_PATH}/bonding/active_slave")"
  IF_PATH="/sys/class/net/${IF}"
fi

if [[ "$IF" == "" || ! -d "$IF_PATH" || ! -f "${IF_PATH}"/statistics/rx_bytes || ! -f "${IF_PATH}"/statistics/tx_bytes ]]; then 
  sleep "${ERROR_DLY}"
  exit 0
fi

if [ -d "${IF_PATH}/wireless" ]; then
  NIC=${label_icon:-$(xrescat i3xrocks.label.wifi )}
else
  NIC=${label_icon:-$(xrescat i3xrocks.label.wired )}
fi

# read dev file and compute net usage
RX1=$(cat "${IF_PATH}"/statistics/rx_bytes)
TX1=$(cat "${IF_PATH}"/statistics/tx_bytes)

sleep "${DLY}"

RX2=$(cat "${IF_PATH}"/statistics/rx_bytes)
TX2=$(cat "${IF_PATH}"/statistics/tx_bytes)

RX_DIFF=$(echo "($RX2-$RX1)/$DLY" | bc)
TX_DIFF=$(echo "($TX2-$TX1)/$DLY" | bc)
RX=$(echo "${RX_DIFF}" | ${NUMFMT})
TX=$(echo "${TX_DIFF}" | ${NUMFMT})
AX=$(echo "($RX_DIFF+$TX_DIFF)" | bc | ${NUMFMT})

# Add a B for bytes at the end if the string is missing a letter
if ! [[ "${RX}" =~ [BKMG]$ ]]; then
  RX="${RX#?}B"
fi

if ! [[ "${TX}" =~ [BKMG]$ ]]; then
  TX="${TX#?}B"
fi

if ! [[ "${AX}" =~ [BKMG]$ ]]; then
  AX="${AX#?}B"
fi

# span for text
fspan() {
  echo "<span font_desc=\"${VALUE_FONT}\" color=\"${VALUE_COLOR}\"> ${1}</span>"
}

# span for label/icon
lspan() {
  echo "<span font_desc=\"${VALUE_FONT}\" color=\"${LABEL_COLOR}\">${1}</span>"
}

# get font specifics from xresource file
VALUE_COLOR=${color:-$(xrescat i3xrocks.value.color "#D8DEE9")}
LABEL_COLOR=${label_color:-$(xrescat i3xrocks.label.color "#7B8394")}
VALUE_FONT=${font:-$(xrescat i3xrocks.value.font "Source Code Pro Medium 13")}

# output net usage using pango markup
if [ "$RT" = "up" ]; then
  echo "$(lspan "${NIC}")$(fspan "$TX")$(lspan "${UP}")"
elif [ "$RT" = "down" ] || [ "$RT" = "dn" ]; then
  echo "$(lspan "${NIC}")$(fspan "$RX")$(lspan "${DN}")"
elif [ "$RT" = "total" ]; then
  echo "$(lspan "${NIC}")$(fspan "$AX")"
else
  echo "$(lspan "${NIC}")$(fspan "$RX") $(lspan "${DN}") /$(fspan "$TX") $(lspan "${UP}")"
fi